Some serial EEPROMs are busy internally after a write command. During that period, a missing acknowledgement can be expected rather than evidence of a disconnected device.

Interpreting the evidence

Compare the timing of the failed access with the device’s write-cycle requirements. Review whether the programming tool waits appropriately before reading or writing again. A persistent lack of response still needs checks of power, addressing and connection, but a brief busy period should be interpreted in context.

Keep this evidence

Send the device reference and the sequence of operations leading to the reported error.

Do not repeatedly power-cycle during a write to obtain a response. Use a suitable supported programming process.

Speak to AXION

For module programming and coding support, send your vehicle details and fault report. Workshop assessment is in Didcot, Oxfordshire. Suitable postal or remote work is confirmed before booking.

Technical background from Microchip. The referenced design explains the principle; the vehicle-specific procedure determines the repair.